Low doses are often enough to maximize performance, so starting small is good practice. Overall, a cup of coffee heightens mental awareness and keeps workers alert during morning meetings and afternoon projects. Recent studies showed that caffeine consumption enhances memory performance.

In particular, it makes memories sharper and easier to recall the next day. In turn, people become less likely to forget important details and facts from previous days. Caffeine enhances working memory, which serves both long-term and short-term benefits.

Memory skills are crucial for most office jobs, and memory enhancement helps with wider job goals. As employees grow further in their careers, they constantly pick up new skills and facts.

Improved memory allows workers to retain new skills and information quickly, strengthening marketable job skills. Better memory also helps with everyday workplace needs.

The accentuated cognitive performance lets employees focus on their jobs fully and do their best work. Many people also use coffee to socialize at work. And connecting with coworkers at the office is a definite perk of any position. Having important bonds with coworkers is another way to improve positivity and productivity in your workspace.

Coffee breaks also benefit work. When employees allow their brains to rest during a brief break, they come back to assignments with a clear head and more energy.

Dividing the workday with breaks makes the day pass faster and improves efficiency. It might revitalize brain activity and give them the boost they need to finish the workday strong.

Everyone takes in new information while at work, whether for a new project or advancement in the field. Because caffeine heightens brain activity, the brain becomes primed to absorb new data.

The drug sharpens new words and information, so the brain identifies them more quickly. Caffeine can also improve focus levels. Focus is crucial at office jobs, helping staff stay on task and maintain deadlines.

Ongoing attention requires energy, and caffeine boosts brain activity so employees can remain in the zone.

However, encourage employees to regulate cups of coffee. Promote a balanced intake to optimize workplace activity. Altogether, keeping coffee in the workplace gives workers another way to power through those longer assignments.

Coffee gives many opportunities to increase creativity at work. Innovation is highly prized at most workplaces, and great workers think originally about improving projects and workflow.

Caffeine helps with all these processes. Its ability to stimulate the brain might jolt creativity into action. Socializing with coffee is another great way to brainstorm creative solutions. In turn, they could bounce around ideas that might not normally appear.

Coffee could create that new idea that takes your department to the next level. Despite all the productivity benefits of coffee, the ultimate effects vary based on the person. While the correct dosage might give an employee a great boost, too much could interfere with sleeping patterns or even induce anxiety.

It all depends on how the body processes caffeine and its tolerance levels. Here are some tips for optimal coffee drinking:. Try experimenting with your coffee to discover the right amount for improved productivity. Caffeine has many benefits, but it detracts from the positives when someone consumes too much.

The U. Food and Drug Administration FDA recommends no more than mg of caffeine per day. Overconsumption can lead to negative physical reactions, such as:.

If someone drinks too much coffee, these adverse symptoms could reduce productivity. Instead of maximizing production levels, it might hinder the ability to perform well. If you or an employee experience these symptoms after drinking coffee, you should probably lower your caffeine intake.

Cut back slowly by a few milligrams per day because an abrupt change in caffeine levels might lead to withdrawal.

Reactions to caffeine ultimately depend on tolerance levels and other sensitivities. For example, people with heart conditions or those taking certain medications might be more susceptible to negative reactions. Find the amount of coffee that allows for the best performance and try not to consume any more than that.

It heightens productivity in the morning and afternoon. A great way to increase coffee accessibility in your workspace is implementing a coffee bar. Our high-quality range of refreshments will enthuse employees and heighten their at-work enjoyment.

We offer a wide range of top-tier beverage brands and state-of-the-art equipment, so your coffee bar lacks nothing. We look forward to hearing from you and finding the best coffee station for you and your team. Home How Coffee Can Improve Office Productivity.

People Love Coffee For the majority of the world, coffee is a necessity. In alone, Americans made their way through But even with those high numbers, America ranks 25th in global coffee consumption.

Finland is the country with the highest amount of coffee drank per capita. Visual Analog Scales VAS. Subjects rated themselves with a mark along a line mm in length. They were heart pounding, headache, sweaty, and upset stomach. The POMS and VAS were completed five times during the sleep deprivation period prior to drug administration at and h on days 1 and 2 and at h on the morning of day 3 2 h before caffeine administration.

POMS and VAS ratings were taken at 1, 2, 4, 8, and 12 h after drug administration. Multiple Sleep Latency Tests. Each modified multiple sleep latency test MSLT was conducted by having the subjects lie in bed in a darkened, sound-attenuated room with their eyes closed.

They were instructed to relax and allow themselves to fall asleep. EEGs, EOGs, and EMGs were displayed on a Grass Electroencephalograph model 8—10D for on-line scoring of awake versus sleep during the MSLT. An experimenter awakened a subject after 30 s of stage 2 sleep or the onset of rapid eye movement REM.

The test was terminated at 20 min if sleep had not occurred. MSLTs were conducted at , , , , , and h on days 1 and 2 of the sleep deprivation period. MSLTs were conducted eight times on day 3 at 1. Stanford Sleepiness Scale. For the Stanford Sleepiness Scale SSS Hoddes et al. The SSS was completed approximately every 2 h throughout the sleep deprivation period at , , , , , , , , , , and h on days 1 and 2.

The SSS was completed eight times on day 3 at 1, 2, 3, 4, 6, 8, 10, and 12 h after drug administration. Measurements of blood pressure, heart rate, and oral temperature were taken at least every 2 h throughout the sleep deprivation period.

After caffeine administration, measurements were taken at 15, 30, 60, 90, , , , and min and then hourly until 13 h after drug administration. Blood samples were collected prior to and at 15, 30, 60, and 90 min, and 2, 2. Results are reported elsewhere Eddington et al.

Separate two-factor repeated measures analysis of variance by using the General Linear Model SAS Institute, Cary, N. were performed for each dependent variable and POMS subscale. The two factors were group or dose and time.

First, each dependent variable was analyzed for group differences and effects of the sleep deprivation period prior to the drug administration by using all measurements made prior to drug administration. Second, each dependent variable was analyzed for the effects of drug and time after drug administration by using the last value obtained prior to drug administration and all values obtained after drug administration.

Statistical results thus reported for the main effects of drug dose, the main effects of time, and an interaction between these main effects. Significant main effects were further evaluated by the Newman-Keuls Multiple Range Test. For each of the tasks, three measures of performance were analyzed: accuracy percent correct , speed responses per unit of time , and throughput number of correct responses per unit of time.

The throughput measure takes both accuracy and speed of performance into account and was subjected to statistical testing.

Predrug means include data for all subjects; there were no differences between the groups prior to drug administration. Performance, Mood, and Physiology Analysis of Variance Summary.

Performance on the choice reaction time task for 8 h after drug administration in subjects who received the mg dose was significantly different from that in subjects who received the placebo.

The mg dose improved performance for 4 h. For subjects receiving the mg dose, performance was not significantly different from that for subjects receiving the placebo at any point following administration.

For subjects receiving the mg dose, performance remained significantly better than that for subjects receiving placebo for 10 h after drug administration, with no significant differences observed among the dose groups at the final h testing period.

Performance on the logical reasoning task by subjects receiving the two highest doses of caffeine was significantly better than by subjects receiving placebo for the entire h period. In addition, caffeine restored performance to the levels obtained after rest during this interval.

Performance after administration of the mg dose was significantly different from that after administration of placebo for 6 h after drug administration.

The effects of sleep deprivation on mood, as measured by the POMS and VAS, are reported in more detail elsewhere Penetar et al. Briefly, the scores of all six subscales of the POMS changed significantly as a result of the sleep deprivation.

Similarly, ratings on the VAS showed the effects of sleep deprivation. Following caffeine administration, significant increases in the POMS vigor subscale and significant decreases in the POMS subscales of fatigue and confusion were observed Table 20—1.

Vigor ratings for all three dose groups were significantly different from those for the placebo group for 2 h after caffeine adminstration. Vigor ratings for the mg dose group were 97 percent of those for subjects in the rested condition 1 h after caffeine administration and remained at 84 percent of those for subjects in the rested condition at the 2-h measurement.

Conversely, fatigue ratings for all three caffeine dose groups decreased significantly for 2 h following caffeine administration.

Confusion ratings in the mg dose group were significantly decreased in comparison with those in the placebo group 2 h after caffeine administration. Caffeine reversed the sleep deprivation effects reported in subjective ratings of alertness for 2 h, energy levels for 12 h, confidence for 2 h, sleepiness for 12 h, and talkativeness for 2 h following drug administration.

Caffeine significantly increased self-rated anxiety for 2 h, and jitteriness or nervousness for 12 h following drug administration. Ratings of heart pounding, headache, sweatiness, and upset stomach were unaffected by caffeine.

For the rested condition day 1 , mean sleep latency periods were between Latency to stage 2 sleep following caffeine administration. Average values of the Stanford Sleepiness Scale increased gradually from 1.

Caffeine's effects were significant for 2 h after drug administration and were not dose-related i. Diastolic blood pressure and oral temperature were significantly affected by caffeine administration Table 20—1 and Figure 20—3. At 1 h after admini stration, both the and the mg doses significantly increased diastolic blood pressure in comparison with the placebo; there were no significant differences at other time points.

The mg dose of caffeine significantly increased oral temperature in comparison with placebo at several measurement times after administration: 2, 2. Neither systolic blood pressure nor pulse was significantly affected. Time course of caffeine effects on four vital signs.

Caffeine was observed to have significant effects on diastolic blood pressure at 1 h and oral temperature from 2 to 12 h after drug administration. See text for details. The study described here indicates that caffeine is effective in reversing the performance degradations and the alterations in mood and alertness produced by periods of prolonged sleep deprivation.

The results indicate that these beneficial effects can be long-lasting and not at the expense of serious mood or physiological side effects. Sleep deprivation degrades cognitive performance. The effects of caffeine on performance in non-sleep-deprived volunteers have been well documented, even at the low dose levels commonly found in food and drink products see Lieberman [] for a review.

The study described here extends the usefulness of caffeine, showing that large doses up to mg are effective in improving a variety of cognitive performances in sleep-deprived individuals, and outlines the time course of its effects in these individuals. The tasks used in the present study were chosen to sample a variety of cognitive abilities with varying mental demands.

Choice reaction time requires little thinking but does require great accuracy and speed. Caffeine produced improved performances of all three tasks, with performance returning to those of rested subjects for up to 12 h after caffeine administration.

Caffeine was not observed to affect recall or code substitution tasks. In toto, these results are in concert with those presented previously Lieberman, ; Roache and Griffiths, and document for the first time the relatively long-lasting effects of this drug on cognitive performance.

The study described here shows that caffeine compares favorably with amphetamine in reversing the effects of sleep deprivation on cognitive performance.

Using an identical sleep deprivation paradigm, Newhouse et al. Sleep deprivation also alters mood and degrades alertness. The present study documents the fact that caffeine can have significant beneficial effects in reversing these mood changes; sleepiness and confusion declined, whereas increases in energy and confidence levels were reported.

Although there were increased ratings of anxiety and jitteriness or nervousness, these effects were not severe and did not elicit complaints from the subjects. Depending on the measure, alertness, which was severely degraded by 49 h of sleep deprivation, was improved for 2 to 4.

In this regard, caffeine was not as effective as amphetamine. The alertness of amphetamine treated subjects 20 mg , as measured by sleep latency tests, was nearly restored to the levels of rested subjects for 7 h Newhouse et al.

Caffeine's effects on alertness are therefore less potent and shorter acting than amphetamine's. Caffeine's effects on physiological measures are important for assessing its usefulness as a stimulant. The study described here shows that relatively high doses of caffeine are well tolerated by sleep-deprived individuals and that its effects are similar to those found in other studies in non-sleep-deprived subjects given lower doses than those used in the present study Myers, ; Newcombe et al.

Additionally, there were no changes in self-reports of other side-effects heart pounding, headache, sweatiness, upset stomach. Of note was caffeine's observed effect on oral temperature. Oral temperature normally rises during the day, from a low in the early morning hours to a peak in the early evening hours.

The subjects in the present study showed this typical response. Caffeine increased temperatures above the normal rise throughout the observation period, again revealing an important aspect of its effects and duration of action.

The significance of this effect awaits further experimentation, although this type of effect has been observed previously with another stimulant, d -amphetamine Newhouse et al. The authors thank the staff of the Behavioral Biology, in particular Sharon Balwinski and Kevin Peyton, for assistance in the conduct of the experiment described here.

Investigators adhered to AR 70—25 and USAMRDC Reg 70—25 on the use of volunteers in research. Use of trade names does not constitute endorsement of product. The views of the authors do not purport to reflect the position of the Department of the Army or the Department of Defense.

HARRIS LIEBERMAN: We have some unpublished data from a couple of studies in which we did find significant effects of caffeine on mood swing. We did not use doses as low as 32 milligrams but used doses of 64 and milligrams of caffeine.

Effects on performance by doses lower than those are hard to detect, but over the long run, over a series of studies, my feeling is that there really are effects with low dosages, and those are the doses that we typically take in our background.

JOEL GRINKER: I was just curious whether in any of the caffeine studies or in any of the other supplement studies age has been looked at systematically as a factor. I have two thoughts, one, that in fact it might potentiate the ability of older individuals or that in fact it has less effectiveness, and I wonder if you have any comments.

DAVID PENETAR: I have here one study that related to age. Typically, these studies were done, with young, healthy males. HARRIS LIEBERMAN: We did look at the age parameter in one of our caffeine studies, but we did not see any significant differences as a function of age or gender.

Do you find much variation that would indicate that shortness of sleep time versus onset of sleep, etc. Are they uniform in your subjects or are they highly individualistic?

DAVID PENETAR: What we do is we bring them into the study the night before and give them 9 hours of time in bed before we start the study, so at that time they are all pretty consistent in the amount of sleep that they have had. Do you find a uniform effect in terms of delay of sleep or shortness of length of sleep, etc?

DAVID PENETAR: We did not specifically look at that because by the time they went to bed it was over 12 hours after they had received caffeine. WILLIAM WATERS: A couple of questions. One pertaining to the onset of parameters.

Did you have a look at whether or not you have any data or whether or not sleep can be induced prior to that?

WILLIAM WATERS: It could be that what you had was a referral of something that might allow it to occur. The other thing was, under the influence of caffeine, did you notice any change in the number, the length, stage one, and arousals? DAVID PENETAR: Again, by the time our subjects went to bed, it was over 12 hours after they had received the caffeine, and we did not see any changes; there were no differences between the groups.

We did monitor them. We recorded them through their sleep, and we saw no differences in sleep architecture, time of sleep, time to bed, or sleep efficiency; we saw no differences for 12 hours. JOHANNA DWYER: I worked with a neurologist who was interested by some observations years ago, when they did a lot more electroconvulsive shock than they do now.

Apparently, they used to prime the patients with caffeine, and by doing this, they could use a lower level of shock and still get the same effect. The reason I bring it up here is not because I hope anyone here is heavily into this, but rather, are there other changes in the electroencephalograms in terms of caffeine's effects that may be in addition to what we have been talking about?

ALLISON YATES: Just one thing. I noticed in some of the graphs that it almost looked as if at milligrams the subjects might have had even a little bit better performance than they had initially in their first 24 hours. This result is important in considering enhancement of performance with normal subjects.

HARRIS LIEBERMAN: Yes, two slides that you showed with my studies, the vigilance and reaction times, were for subjects who had stayed up all night the night before and who were back in the morning after the administration.

Their performances were similar to those with placebos under the same conditions. I consider that to be above normal, although since caffeine is such a common component of the diet, it is hard to untangle it all.

HARRIS LIEBERMAN: We typically include that as a parameter in our studies and look to see whether there are differences between moderate, low, and heavy caffeine users in their responsiveness, and in the low and moderate range there is not much difference.

When you get to the real high users, you see big differences in responsiveness. That depends on the timing of administration, whether they are in a deprivation stage, or whether they are already on a lot caffeine. HARRIS LIEBERMAN: Average caffeine consumption is about milligrams per day, which is maybe three cups of not very strong coffee.

I define high for the purpose of categorizing subjects as above or milligrams per day. We used to always think that members of the Army must be heavy coffee drinkers because you get that perception, but looking out in field studies where soldiers are eating rations, we found out that even though you gave a meal ready-to-eat, 90 percent of the coffee packets were returned unused.

The rest of the 10 percent probably went mostly to the senior sergeants, who had a chance to stay by the talking place and make some coffee for themselves.

So young soldiers in the field today are not heavy coffee drinkers. I am sure they drink plenty of caffeine if they have carbonated beverages. But most of the time carbonated beverages are not available to them in the field, although maybe in Desert Storm cans of Coke manged to get inside of the tanks anyway.

My question is, has anybody done sleep studies on evaluating caffeine using the vehicle of delivering the caffeine in the form of a cola or in the form of a coffee beverage itself?

DAVID PENETAR: A number of studies look at coffee drinking when they give caffeine. In fact, in some of the studies reported here, they took decaffeinated coffee and added caffeine to it, and the subjects drank it that way.

In other studies it was either caffeine pills or caffeine powder dissolved in some drink. For instance, I am sure your subjects knew when they were receiving a placebo. DAVID PENETAR: Ours was powdered caffeine dissolved in a lemon juice drink, and the lemon juice drink was very bitter.

As you know, caffeine powders are very bitter, so they could not tell what they were drinking other than lemon juice drink. WILLIAM BEISEL: So many of the emergency rations and so on seem to be candy bars with chocolate flavoring. How much of that is caffeine?

DAVID PENETAR: Milk chocolate has about 7 milligrams per ounce, whereas bakery chocolate or unsweetened chocolate has about 35 milligrams per ounce. They figure that, for example, a Hershey's candy bar has 25 to 35 milligrams per ounce, so it is not a lot, and it is less than most sodas.

Penetar, Walter Reed Army Institute of Research, Washington, D. Subjects were paid for their participation. The investigators adhered to AR 70—25 U.

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Show details Institute of Medicine US Committee on Military Nutrition Research; Marriott BM, editor. Contents Hardcopy Version at National Academies Press.

Search term. EFFECTS OF CAFFEINE ON MOOD AND ALERTNESS Several questionnaires and methods have been used to assess caffeine's effects on mood.

MATERIALS AND METHODS Subjects Fifty normal, healthy, nonsmoking, drug-free males between the ages of 18 and 32 mean age, Procedure Subjects arrived in the laboratory in groups of three to four each on the evening before the sleep deprivation period began.

Mood Measures Profile of Mood States. Alertness Measures Multiple Sleep Latency Tests. Vital Signs Measurements of blood pressure, heart rate, and oral temperature were taken at least every 2 h throughout the sleep deprivation period. Catecholamine and Caffeine Assays Blood samples were collected prior to and at 15, 30, 60, and 90 min, and 2, 2.

Statistical Analysis Separate two-factor repeated measures analysis of variance by using the General Linear Model SAS Institute, Cary, N. RESULTS Performance Tests For each of the tasks, three measures of performance were analyzed: accuracy percent correct , speed responses per unit of time , and throughput number of correct responses per unit of time.

TABLE 20—1 Performance, Mood, and Physiology Analysis of Variance Summary. Mood Measures The effects of sleep deprivation on mood, as measured by the POMS and VAS, are reported in more detail elsewhere Penetar et al.

Alertness Measures Multiple Sleep Latency Tests For the rested condition day 1 , mean sleep latency periods were between FIGURE 20—2 Latency to stage 2 sleep following caffeine administration.

Stanford Sleepiness Scale Average values of the Stanford Sleepiness Scale increased gradually from 1. TABLE 20—2 Stanford Sleepiness Scale Scores.

Vital Signs Diastolic blood pressure and oral temperature were significantly affected by caffeine administration Table 20—1 and Figure 20—3. FIGURE 20—3 Time course of caffeine effects on four vital signs.

Doses of mg are needed to reverse severely degraded performance as a result of long periods of sleep deprivation. Presumably, lower doses — mg would be effective in ameliorating the changes caused by shorter periods of deprivation.

Use of caffeine should be restricted to special situations when sleep has been unusually disrupted and for the benefit of temporarily 10—12 h restoring alertness and sustaining performance during critical periods of military operations.

Finally, although caffeine can temporarily sustain performance during continuous operations, it should be emphasized that no drug can substitute for adequate sleep.

See U. Department of the Army. Babkoff, H. Mikulincer, T. Caspy, R. Carasso, and H. Sing a The implications of sleep loss for circadian performance accuracy.

Work Stress — Sing, D. Thorne, S. Genser, and F. Hegge b Perceptual distortions and hallucinations reported during the course of sleep deprivation.

Perceptual Motor Skills — Baddeley, A. A 3-minute test based on grammatical transformations. Psychonomic Sci. Battig, K. Buzzi, J. Martin, and J. Feierabend The effects of caffeine on physiological functions and mental performance.

Experentia — Bruce, M. Scott, M. Lader, and V. Marks The psychopharmacological and electrophysiological effects of single doses of caffeine in healthy human subjects.

Chait, L. Griffiths Effects of caffeine on cigarette smoking and subjective response. Childs, J. Caffeine consumption and target scanning performance.

Factors — Choi, O. Shamin, W. Padgett, and J. Daly Caffeine and theophylline analogues: Correlation of behavioral effects with activity as adenosine receptor antagonists and as phosphodiesterase inhibitors.

Life Sci. Curatolo, P. Robertson The health consequences of caffeine. Dews, P. Behavioral effects of caffeine. B Dews, editor. New York: Springer-Verlag. Eddington, N. Lugo, G. Kamimori, E. Fadiran, D. Penetar The influence of caffeine administration on in-vivo catecholamine pharmacodynamics in sleep deprived volunteers.

Fredholm, B. On the mechanism of action of theophylline and caffeine. Acta Med. Ghoneim, M. Hinrichs, C. Chiang, and W. Loke Pharmacokinetic and pharmacodynamic interactions between caffeine and diazepam. Goldstein, A. Warren, and S. Kaizer Psychotropic effects of caffeine in man.

Individual differences in sensitivity to caffeine-induced wakefulness. Therapeutics — Griffiths, R. Woodson Reinforcing effects of caffeine in humans. Hoddes, E.

Zarcone, H. Smythe, R. Phillips, and W. Dement Quantification of sleepiness: A new approach. Psychophysiology — Jacobson, B. Edgley Effects of caffeine on simple reaction time and movement time.

Space Environ. Kuznicki, J. Turner

Subjects viewed a 6-by-6 block of squares with 36 red and green squares arranged in random order each block contained an equal number of red and green squares.

This task of immediate recall allowed subjects to view the arrangements for as long as they liked and then press a key to present two choices, one of which matched the original set of squares. They were required to pick the correct matching square.

Twenty trials were presented. Reaction Time. A choice reaction time task was used to measure reaction time. The visual-motor task required subjects to press the numbered keyboard keys corresponding to numbers presented on the screen. The digits 0 through 9 appeared one at a time in the center of the screen.

The stimulus remained on until a response was made. Fifty numbers were presented. Profile of Mood States. The Profile of Mood States POMS McNair et al. Subjects rated themselves on each adjective from 1 not at all to 5 extremely.

Visual Analog Scales VAS. Subjects rated themselves with a mark along a line mm in length. They were heart pounding, headache, sweaty, and upset stomach. The POMS and VAS were completed five times during the sleep deprivation period prior to drug administration at and h on days 1 and 2 and at h on the morning of day 3 2 h before caffeine administration.

POMS and VAS ratings were taken at 1, 2, 4, 8, and 12 h after drug administration. Multiple Sleep Latency Tests. Each modified multiple sleep latency test MSLT was conducted by having the subjects lie in bed in a darkened, sound-attenuated room with their eyes closed.

They were instructed to relax and allow themselves to fall asleep. EEGs, EOGs, and EMGs were displayed on a Grass Electroencephalograph model 8—10D for on-line scoring of awake versus sleep during the MSLT.

An experimenter awakened a subject after 30 s of stage 2 sleep or the onset of rapid eye movement REM. The test was terminated at 20 min if sleep had not occurred. MSLTs were conducted at , , , , , and h on days 1 and 2 of the sleep deprivation period. MSLTs were conducted eight times on day 3 at 1.

Stanford Sleepiness Scale. For the Stanford Sleepiness Scale SSS Hoddes et al. The SSS was completed approximately every 2 h throughout the sleep deprivation period at , , , , , , , , , , and h on days 1 and 2.

The SSS was completed eight times on day 3 at 1, 2, 3, 4, 6, 8, 10, and 12 h after drug administration. Measurements of blood pressure, heart rate, and oral temperature were taken at least every 2 h throughout the sleep deprivation period.

After caffeine administration, measurements were taken at 15, 30, 60, 90, , , , and min and then hourly until 13 h after drug administration. Blood samples were collected prior to and at 15, 30, 60, and 90 min, and 2, 2.

Results are reported elsewhere Eddington et al. Separate two-factor repeated measures analysis of variance by using the General Linear Model SAS Institute, Cary, N.

were performed for each dependent variable and POMS subscale. The two factors were group or dose and time. First, each dependent variable was analyzed for group differences and effects of the sleep deprivation period prior to the drug administration by using all measurements made prior to drug administration.

Second, each dependent variable was analyzed for the effects of drug and time after drug administration by using the last value obtained prior to drug administration and all values obtained after drug administration.

Statistical results thus reported for the main effects of drug dose, the main effects of time, and an interaction between these main effects. Significant main effects were further evaluated by the Newman-Keuls Multiple Range Test. For each of the tasks, three measures of performance were analyzed: accuracy percent correct , speed responses per unit of time , and throughput number of correct responses per unit of time.

The throughput measure takes both accuracy and speed of performance into account and was subjected to statistical testing. Predrug means include data for all subjects; there were no differences between the groups prior to drug administration. Performance, Mood, and Physiology Analysis of Variance Summary.

Performance on the choice reaction time task for 8 h after drug administration in subjects who received the mg dose was significantly different from that in subjects who received the placebo.

The mg dose improved performance for 4 h. For subjects receiving the mg dose, performance was not significantly different from that for subjects receiving the placebo at any point following administration.

For subjects receiving the mg dose, performance remained significantly better than that for subjects receiving placebo for 10 h after drug administration, with no significant differences observed among the dose groups at the final h testing period.

Performance on the logical reasoning task by subjects receiving the two highest doses of caffeine was significantly better than by subjects receiving placebo for the entire h period.

In addition, caffeine restored performance to the levels obtained after rest during this interval. Performance after administration of the mg dose was significantly different from that after administration of placebo for 6 h after drug administration.

The effects of sleep deprivation on mood, as measured by the POMS and VAS, are reported in more detail elsewhere Penetar et al. Briefly, the scores of all six subscales of the POMS changed significantly as a result of the sleep deprivation.

Similarly, ratings on the VAS showed the effects of sleep deprivation. Following caffeine administration, significant increases in the POMS vigor subscale and significant decreases in the POMS subscales of fatigue and confusion were observed Table 20—1. Vigor ratings for all three dose groups were significantly different from those for the placebo group for 2 h after caffeine adminstration.

Vigor ratings for the mg dose group were 97 percent of those for subjects in the rested condition 1 h after caffeine administration and remained at 84 percent of those for subjects in the rested condition at the 2-h measurement. Conversely, fatigue ratings for all three caffeine dose groups decreased significantly for 2 h following caffeine administration.

Confusion ratings in the mg dose group were significantly decreased in comparison with those in the placebo group 2 h after caffeine administration. Caffeine reversed the sleep deprivation effects reported in subjective ratings of alertness for 2 h, energy levels for 12 h, confidence for 2 h, sleepiness for 12 h, and talkativeness for 2 h following drug administration.

Caffeine significantly increased self-rated anxiety for 2 h, and jitteriness or nervousness for 12 h following drug administration. Ratings of heart pounding, headache, sweatiness, and upset stomach were unaffected by caffeine.

For the rested condition day 1 , mean sleep latency periods were between Latency to stage 2 sleep following caffeine administration. Average values of the Stanford Sleepiness Scale increased gradually from 1. Caffeine's effects were significant for 2 h after drug administration and were not dose-related i.

Diastolic blood pressure and oral temperature were significantly affected by caffeine administration Table 20—1 and Figure 20—3. At 1 h after admini stration, both the and the mg doses significantly increased diastolic blood pressure in comparison with the placebo; there were no significant differences at other time points.

The mg dose of caffeine significantly increased oral temperature in comparison with placebo at several measurement times after administration: 2, 2. Neither systolic blood pressure nor pulse was significantly affected. Time course of caffeine effects on four vital signs. Caffeine was observed to have significant effects on diastolic blood pressure at 1 h and oral temperature from 2 to 12 h after drug administration.

See text for details. The study described here indicates that caffeine is effective in reversing the performance degradations and the alterations in mood and alertness produced by periods of prolonged sleep deprivation.

The results indicate that these beneficial effects can be long-lasting and not at the expense of serious mood or physiological side effects. Sleep deprivation degrades cognitive performance.

The effects of caffeine on performance in non-sleep-deprived volunteers have been well documented, even at the low dose levels commonly found in food and drink products see Lieberman [] for a review.

The study described here extends the usefulness of caffeine, showing that large doses up to mg are effective in improving a variety of cognitive performances in sleep-deprived individuals, and outlines the time course of its effects in these individuals.

The tasks used in the present study were chosen to sample a variety of cognitive abilities with varying mental demands. Choice reaction time requires little thinking but does require great accuracy and speed. Caffeine produced improved performances of all three tasks, with performance returning to those of rested subjects for up to 12 h after caffeine administration.

Caffeine was not observed to affect recall or code substitution tasks. In toto, these results are in concert with those presented previously Lieberman, ; Roache and Griffiths, and document for the first time the relatively long-lasting effects of this drug on cognitive performance.

The study described here shows that caffeine compares favorably with amphetamine in reversing the effects of sleep deprivation on cognitive performance. Using an identical sleep deprivation paradigm, Newhouse et al.

Sleep deprivation also alters mood and degrades alertness. The present study documents the fact that caffeine can have significant beneficial effects in reversing these mood changes; sleepiness and confusion declined, whereas increases in energy and confidence levels were reported.

Although there were increased ratings of anxiety and jitteriness or nervousness, these effects were not severe and did not elicit complaints from the subjects.

Depending on the measure, alertness, which was severely degraded by 49 h of sleep deprivation, was improved for 2 to 4. In this regard, caffeine was not as effective as amphetamine. The alertness of amphetamine treated subjects 20 mg , as measured by sleep latency tests, was nearly restored to the levels of rested subjects for 7 h Newhouse et al.

Caffeine's effects on alertness are therefore less potent and shorter acting than amphetamine's. Caffeine's effects on physiological measures are important for assessing its usefulness as a stimulant.

The study described here shows that relatively high doses of caffeine are well tolerated by sleep-deprived individuals and that its effects are similar to those found in other studies in non-sleep-deprived subjects given lower doses than those used in the present study Myers, ; Newcombe et al.

Additionally, there were no changes in self-reports of other side-effects heart pounding, headache, sweatiness, upset stomach. Of note was caffeine's observed effect on oral temperature. Oral temperature normally rises during the day, from a low in the early morning hours to a peak in the early evening hours.

The subjects in the present study showed this typical response. Caffeine increased temperatures above the normal rise throughout the observation period, again revealing an important aspect of its effects and duration of action. The significance of this effect awaits further experimentation, although this type of effect has been observed previously with another stimulant, d -amphetamine Newhouse et al.

The authors thank the staff of the Behavioral Biology, in particular Sharon Balwinski and Kevin Peyton, for assistance in the conduct of the experiment described here.

Investigators adhered to AR 70—25 and USAMRDC Reg 70—25 on the use of volunteers in research. Use of trade names does not constitute endorsement of product. The views of the authors do not purport to reflect the position of the Department of the Army or the Department of Defense.

HARRIS LIEBERMAN: We have some unpublished data from a couple of studies in which we did find significant effects of caffeine on mood swing. We did not use doses as low as 32 milligrams but used doses of 64 and milligrams of caffeine. Effects on performance by doses lower than those are hard to detect, but over the long run, over a series of studies, my feeling is that there really are effects with low dosages, and those are the doses that we typically take in our background.

JOEL GRINKER: I was just curious whether in any of the caffeine studies or in any of the other supplement studies age has been looked at systematically as a factor. I have two thoughts, one, that in fact it might potentiate the ability of older individuals or that in fact it has less effectiveness, and I wonder if you have any comments.

DAVID PENETAR: I have here one study that related to age. Typically, these studies were done, with young, healthy males. HARRIS LIEBERMAN: We did look at the age parameter in one of our caffeine studies, but we did not see any significant differences as a function of age or gender.

Do you find much variation that would indicate that shortness of sleep time versus onset of sleep, etc. Are they uniform in your subjects or are they highly individualistic? DAVID PENETAR: What we do is we bring them into the study the night before and give them 9 hours of time in bed before we start the study, so at that time they are all pretty consistent in the amount of sleep that they have had.

Do you find a uniform effect in terms of delay of sleep or shortness of length of sleep, etc? DAVID PENETAR: We did not specifically look at that because by the time they went to bed it was over 12 hours after they had received caffeine.

WILLIAM WATERS: A couple of questions. One pertaining to the onset of parameters. Did you have a look at whether or not you have any data or whether or not sleep can be induced prior to that? WILLIAM WATERS: It could be that what you had was a referral of something that might allow it to occur.

The other thing was, under the influence of caffeine, did you notice any change in the number, the length, stage one, and arousals? DAVID PENETAR: Again, by the time our subjects went to bed, it was over 12 hours after they had received the caffeine, and we did not see any changes; there were no differences between the groups.

We did monitor them. We recorded them through their sleep, and we saw no differences in sleep architecture, time of sleep, time to bed, or sleep efficiency; we saw no differences for 12 hours.

JOHANNA DWYER: I worked with a neurologist who was interested by some observations years ago, when they did a lot more electroconvulsive shock than they do now. Apparently, they used to prime the patients with caffeine, and by doing this, they could use a lower level of shock and still get the same effect.

The reason I bring it up here is not because I hope anyone here is heavily into this, but rather, are there other changes in the electroencephalograms in terms of caffeine's effects that may be in addition to what we have been talking about? ALLISON YATES: Just one thing. I noticed in some of the graphs that it almost looked as if at milligrams the subjects might have had even a little bit better performance than they had initially in their first 24 hours.

This result is important in considering enhancement of performance with normal subjects. HARRIS LIEBERMAN: Yes, two slides that you showed with my studies, the vigilance and reaction times, were for subjects who had stayed up all night the night before and who were back in the morning after the administration.

Their performances were similar to those with placebos under the same conditions. I consider that to be above normal, although since caffeine is such a common component of the diet, it is hard to untangle it all. HARRIS LIEBERMAN: We typically include that as a parameter in our studies and look to see whether there are differences between moderate, low, and heavy caffeine users in their responsiveness, and in the low and moderate range there is not much difference.

When you get to the real high users, you see big differences in responsiveness. That depends on the timing of administration, whether they are in a deprivation stage, or whether they are already on a lot caffeine.

HARRIS LIEBERMAN: Average caffeine consumption is about milligrams per day, which is maybe three cups of not very strong coffee. I define high for the purpose of categorizing subjects as above or milligrams per day.

We used to always think that members of the Army must be heavy coffee drinkers because you get that perception, but looking out in field studies where soldiers are eating rations, we found out that even though you gave a meal ready-to-eat, 90 percent of the coffee packets were returned unused.

The rest of the 10 percent probably went mostly to the senior sergeants, who had a chance to stay by the talking place and make some coffee for themselves. So young soldiers in the field today are not heavy coffee drinkers. I am sure they drink plenty of caffeine if they have carbonated beverages.

But most of the time carbonated beverages are not available to them in the field, although maybe in Desert Storm cans of Coke manged to get inside of the tanks anyway. My question is, has anybody done sleep studies on evaluating caffeine using the vehicle of delivering the caffeine in the form of a cola or in the form of a coffee beverage itself?

DAVID PENETAR: A number of studies look at coffee drinking when they give caffeine. In fact, in some of the studies reported here, they took decaffeinated coffee and added caffeine to it, and the subjects drank it that way.

In other studies it was either caffeine pills or caffeine powder dissolved in some drink. For instance, I am sure your subjects knew when they were receiving a placebo. DAVID PENETAR: Ours was powdered caffeine dissolved in a lemon juice drink, and the lemon juice drink was very bitter.

As you know, caffeine powders are very bitter, so they could not tell what they were drinking other than lemon juice drink. WILLIAM BEISEL: So many of the emergency rations and so on seem to be candy bars with chocolate flavoring. How much of that is caffeine? DAVID PENETAR: Milk chocolate has about 7 milligrams per ounce, whereas bakery chocolate or unsweetened chocolate has about 35 milligrams per ounce.

They figure that, for example, a Hershey's candy bar has 25 to 35 milligrams per ounce, so it is not a lot, and it is less than most sodas. Penetar, Walter Reed Army Institute of Research, Washington, D. Subjects were paid for their participation. The investigators adhered to AR 70—25 U.

Department of the Army, and U. Army Medical Research and Development Command Reg 70—25 , on the use of volunteers in research. Turn recording back on. National Library of Medicine Rockville Pike Bethesda, MD Web Policies FOIA HHS Vulnerability Disclosure.

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Show details Institute of Medicine US Committee on Military Nutrition Research; Marriott BM, editor. Contents Hardcopy Version at National Academies Press.

Search term. EFFECTS OF CAFFEINE ON MOOD AND ALERTNESS Several questionnaires and methods have been used to assess caffeine's effects on mood. MATERIALS AND METHODS Subjects Fifty normal, healthy, nonsmoking, drug-free males between the ages of 18 and 32 mean age, Procedure Subjects arrived in the laboratory in groups of three to four each on the evening before the sleep deprivation period began.

Mood Measures Profile of Mood States. Drink a cup of joe and you'll remember more things from meetings, solve problems faster and be able to focus on and complete tasks more productively throughout the day.

Related: How a Coffee Startup Chose its Crowdsourced Logo. Subjectively, most people agree that coffee also helps them feel better -- especially when they wake up feeling particularly tired or fatigued.

Ordinarily, feeling tired can leave you less alert and less focused, but coffee can help mitigate those effects -- and may also boost your physical performance if your job requires anything physical. Caffeine also serves to reduce inflammation in the body, which serves as a quick mode of pain relief , and may reduce headaches and other points of soreness that can interfere with work.

In addition, coffee stimulates the release of dopamine, a feel-good chemical in the brain , improving your mood and helping to stabilize your emotions so you feel better throughout the work day. Better emotional stability and less tiredness means you'll get more done.

Coffee may also has some health benefits, which can keep us from getting sick and keep us working healthier and living longer.

For example, drinking coffee every day in moderate quantities may reduce your risk for developing Type 2 diabetes , and serves as an antioxidant in the body, eliminating harmful free radicals that damage cells and otherwise leave the body vulnerable to a host of different conditions.

That means you may be taking fewer sick days, and you'll be in better physical condition to maximize your productivity. Unfortunately, the anti-tiredness effects of caffeine also have a dangerous, and obvious, side effect. The effects of caffeine last for several hours, depending on the individual, so consuming coffee even within eight hours of bedtime can interfere with your ability to sleep that night.

This results in you getting fewer hours of sleep, leading you to drink more coffee to make up for your tiredness the next day, and creating a vicious cycle that can leave you more fatigued than ever. Eventually, you'll need to repay your sleep debt , and if you don't, the effects of sleep deprivation will start to accumulate -- regardless of how much coffee you drink.

Eventually, that will take a toll on your productivity. Caffeine stimulates the production of adrenaline -- the fight-or-flight chemical in the brain that's usually produced as a result of stress. In small quantities, this can give us a boost of energy, but if you're prone to anxiety or have an anxiety or panic disorder, caffeine can exacerbate those problems.

Excessive coffee drinking can trigger panic attacks in vulnerable individuals, and lead to increased anxiety and restlessness in others. If you end up drinking more coffee than usual, this can leave you a fidgeting mess, with your mind racing.

You'll also be unable to settle down enough to get your work done. Don't forget that caffeine is still a drug and that your brain can become physically dependent on it.

Realize, too, that you'll become more tolerant to caffeine over time, resulting in slightly decreased effects.

Then, should you go a day or two without caffeine, you'll start to experience the physical effects of withdrawal.

Basically, coffee becomes less effective over time, and if you ever decide to stop drinking it, you'll temporarily face a significant drop in perceived wellness and productivity. So, does caffeine help or hurt you? For the most part, it's clear that caffeine will improve your productivity.

Granted, these effects will not be as pronounced as taking a stimulant but they are part of a better long term strategy for promoting focus and wakefulness. One of the most obvious methods to feel less tired is to get more sleep. We delve into this topic in POWER Mornings , but the key is to maintain consistent bedtime and wake-time routines.

Exercise is a great way to feel more alert, sleep better, and boost your energy. This is true in the long-term e. But exercise is also effective in the short term. Try a morning walk, jumping jacks, or pushups for an instant energy boost. A walk after lunch can also be a healthier substitute for a second cup of coffee and has other health benefits as well.

Then when you do partake the effects are more pronounced. Here are a few of my favorite situations where I choose to use caffeine for an extra boost in productivity.

I say this as someone with a 1-month-old baby sleeping in my bedroom currently. Drinking coffee beforehand can help you feel more energized and alert so you can be better at loving people.

I also drink coffee before I speak in front of people or an important meeting. In summary, coffee is a wonderful gift from God. And by using it strategically, you can improve your productivity without becoming dependent on it. Yes, add me to your mailing list. Submit comment. I have not been able to take in caffeine for years due to heart rhythm issues.

I miss the help in staying awake in the afternoon. Nowadays, I have a desk chair that reclines comfortably and I often set my phone alarm for 30 minutes and lean back for a power nap in the afternoon. Membership Log In Menu About Store Resources Newsletter Articles Podcast YouTube Member Login Become a Member.

Personal Development. April 6, by Reagan Rose 9 min read.